Have you ever wondered why February 29 is a leap day? According to this
neat BBC article about Leap Day, you can blame the Roman Emperor Augustus:

Why is February 29, not February 31, a leap year day? All the other
months have 30 or 31 days, but February suffered from the ego of Roman
Emperor Caesar Augustus, says Stewart. Under Julius Caesar, February
had 30 days, but when Caesar Augustus was emperor he was peeved that
his month - August - had only 29 days, whereas the month named after
his predecessor Julius - July - had 31. "He pinched a couple of
days for August to make it the same as July. And it was poor old February
that lost out," says Prof Stewart.